This invention relates to the naphthyridone antibiotic trovafloxacin. More particularly, it relates to polymorphs and the pentahydrate of the zwitterionic form of thereof having the formula I, below, and methods for their preparation. The invention further relates to methods of using, and pharmaceutical compositions comprising, the compounds of the invention for treatment of bacterial infections in mammals. The antibacterial activity of the aforementioned naphthyridone antiliotic is described in U.S. Pat. Nos. 5,164,402 [the '402 patent] and 5,229,396 issued Nov. 17, 1992 and Jul. 20, 1993, respectively, the disclosures of which are hereby incorporated herein by reference in their entirety. The foregoing patents are assigned in common with the present application.
The zwitterionic forms of trovafloxacin are useful for the administration of the drug as a suspension.